In an increasingly networked world, more and more traffic, such as data, voice, and video, is transmitted over public and proprietary networks. Wireless networks, in particular, are becoming increasingly popular as networks through which subscribers obtain both voice services (e.g., telephone calls) and data services (e.g., email and web surfing). For data services, the wireless device may be connected, through the wireless network, to a data network, such as the Internet.
Network address translation (NAT) is the process of modifying network address information in datagram (e.g., packet) headers while in transit across a traffic routing device for the purpose of remapping one address space into another. One use of NAT is that it allows for a single Internet protocol (IP) address to be shared among a number of devices, such as portable wireless devices, thus increasing the effective number of addresses from which a service provider can choose when allocating addresses to the portable wireless devices.
In one type of NAT address sharing, in addition to allocating IP addresses, NAT may also be used to allocate a port range. Thus, a particular connecting wireless device may be assigned an IP address and a range of ports that are useable by the device. By allocating port ranges in addition to IP addresses, the effective address space that the service provider uses when assigning addresses to the portable wireless devices, may be increased significantly.